Sex pheromones to control tomato moth Tuta absoluta (Meyrick) (Lep., Gelechiidae)

Abstract

Tuta absoluta (Lepidoptera: Gellechiidae) is an important pest of tomato. Its control is based on chemical insecticides, some of which have lost their effectivity probably due to the selection of resistant populations of the insect. Sex pheromones have been successfully used to control many insect pests; however, studies related to the control of T. absoluta are scarce. The goal of this study was to evaluate the effect of sex pheromones on male behavior in greenhouse conditions. The first step was to determine the durability of male attraction to rubber septa dispensers loaded with 0,2 mg of the pheromone, which according to our results can be estimated to last for at least 105 days. Then, the effect of sex pheromones on male behavior was evaluated. Male captures in traps baited either with pheromone septa or virgin females were used as indicators of the efficacy of the treatments. Two dispenser densities (16.000 and 32.000 per hectare), with and without a sticky surface as a mortality factor, were evaluated. A significant shutdown of male captures was observed at both dispenser densities, with a slightly stronger effect at higher densities. The addition of the sticky surface did not improved effectivity. Finally, 3.200 dispensers were located in a 1.000-m² commercial greenhouse, resulting in a strong reduction of male captures with respect to an untreated greenhouse that served as control. Reduction of trap captures were more than 96 % for the first 78 days after dispenser installation, falling to 92 % at 106 days. These results show that sex pheromone of T. absoluta affects male behavior and could be an important tool to control this pest.